Reducing cognitive demand fails to mitigate choice overload: Multimodal neural and gaze evidence for effort conservation

Summary: An overabundance of options can impair decision-making, a phenomenon known as choice overload. Modern platforms use recommendation and filtering tools to mitigate this by lowering cognitive demand, yet whether these strategies actually improve choices remains unclear. We conducted two experiments that manipulated cognitive demand—by presenting high-attractiveness option sets or by providing a shortlist tool—while recording eye-tracking and electroencephalography (EEG) as participants chose from sets of 6–24 options. Reducing demand accelerated decisions but did not improve choice performance as set size increased. Under low-demand conditions, eye-gaze measures revealed narrower visual search and fixation-locked EEG showed shorter event-related potential latencies and weaker occipital alpha suppression, and the three modalities co-varied within individuals, indicating that participants conserved rather than reallocated cognitive effort. These findings demonstrate that simplifying decisions can backfire: when choices feel easier, people disengage rather than optimize, leaving choice overload intact. Effective choice architecture should therefore sustain deliberation, not merely reduce demand.